<!DOCTYPE html>
<html lang="zh-CN">
    <head>
        <meta charset="UTF-8" />
        <title>01_复习</title>

        <script>
            var btn = document.getElementById('btn');
            btn.onclick = function (){
                alert('我爱你');
            }
        </script>


    </head>
    <body>
        <button onclick="alert('扫毒3');" id="btn">按钮</button>

        <script src="./js/01_复习.js"></script>
    </body>
</html>